Different forms of stress have been utilized with echocardiographic imaging of the heart for evaluation of ischemic heart disease. Among all different forms of stress, dobutamine potentially offers the advantage of assessing the ischemic threshold (the myocardial work load at which ischemia develops). However, whether this measurement indeed correlates with indices associated with poor prognosis in coronary artery disease has not been determined. To address this issue, we studied 58 patients (51 men; age 61plus/minus9 years) with coronary artery disease. Patients underwent dobutamine stress with simultaneous visualization of the myocardium by means of transesophageal echocardiography. The ischemic threshold was defined as the dose of dobutamine at which worsening of regional wall motion was first detected. The ischemic threshold was progressively lower with a greater extent of coronary artery disease (patients with three-vessel disease had a significantly lower ischemic threshold compared to patients with only one-vessel disease). The ischemic threshold also significantly correlated with the change in ejection fraction with exercise measured by radionuclide angiography (the lower the ischemic threshold during dobutamine infusion, the greater the fall in ejection fraction during exercise). Hence, in patients with coronary artery disease, the ischemic threshold measured during dobutamine stress echocardiography is significantly related to known indices associated with poor prognosis. These findings emphasize the usefulness of dobutamine stress combined with echocardiography for the assessment of patients with coronary artery disease.